Tag Archives: Enduron

Weir Minerals completes Enduron HPGR first at mine site

Comminution of minerals, Mineral processing, Mining equipment, Mining services, , , ,

Weir Minerals continues to make inroads in the comminution market, with the company having achieved a major high pressure grinding roll (HPGR) milestone during 2023, Weir Group’s 2023 financial year results confirmed.

In a Weir Group report that highlighted flat year-on-year orders and a 16% increase in adjusted profit, the Minerals division noted a significant increase in its aftermarket solutions.

“This reflects growth in our installed base, and our increased strategic focus on this area,” Weir Group said in the results. “A particular highlight was an order from a large copper mine in South America, where our customer ordered Enduron® rollers for their HPGR.”

The installation will be the first instance of Weir Minerals’ rollers being fitted to a competitor’s HPGR, enabling the company to showcase the performance and reliability benefits of its technology, it said.

It concluded on this area: “More generally, the pipeline for our HPGR remains strong with a number of projects advancing materially throughout the year.”

Weir Minerals says the Enduron HPGR is a market proven model with the mechanical design to support efficient and durable skewing thanks to its unique bearing arrangement and control philosophy. It has a unique roll diameter-width ratio, which maximises throughput at the desired product grind. Self-adjusting cheek plates provide equal sealing distance as flanges at minimum costs, according to the OEM.

Alongside this, Weir Minerals also gained further market share in 2023 in mill circuit pumps, converting over 85% of its competitive field trials.

Brownfield expansions and sustainable mining projects boost Weir Group Q1 orders

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Weir Group continued to benefit from relatively high commodity prices, tightness in physical inventories of metals and minerals, and strong end market demand for commodities in the March quarter, registering a 22% boost in original equipment order growth in the three-month period.

The company said brownfield activity and sustainability projects were behind this leap in orders.

“Customers are ordering Weir solutions to debottleneck, expand and improve the sustainability of existing mines, while also increasingly engaging on new sustainability driven technologies, such as our redefined mill circuit and the Motion Metrics digital offering,” the company said in its results.

Weir Group’s “redefined mill circuit” encompasses Weir Minerals’ Enduron® high pressure grinding rolls, along with the additions of technologies from Eriez and Swiss Tower Mills (STM) Minerals, which are part of specific partnerships. These solutions are enabling it to redefine the mining mill circuit so customers can use less energy, use water wisely and create less waste during minerals processing, it says.

Weir Minerals recently announced the completion of the STM Minerals AG vertical stirred mill commissioning at the Weir Technology Hub in the Netherland. Regarding Eriez, the combination of pumps, cyclones, classification equipment, and other mill circuit products supplied by Weir Minerals, along with Eriez’s HydroFloat, StackCell®, columns and sparging systems, allows owners to take advantage of well-matched equipment designed and tested as a system, Weir says. This makes Weir a natural fit for contributing to Coarse Particle Flotation flowsheets, it added.

In terms of the Weir’s outlook, it said in its March quarter results: “The business is executing well and conditions in our mining markets are positive. High levels of activity and demand for our aftermarket spares and brownfield original equipment solutions are driving order book growth. Our guidance for 2023 is reiterated and we expect to deliver growth in constant currency revenue, profit and operating margin. We are on track to deliver our target of 17% operating margin in 2023, supported by operational efficiencies and early benefits from Performance Excellence.

“Further out, the long-term fundamentals for mining and our business are highly attractive, underpinned by decarbonisation, GDP growth and the transition to sustainable mining. We have a clear strategy to grow ahead of our markets, with specific growth initiatives underpinning our ambition to deliver through-cycle mid-to-high single digit percentage revenue growth.”

Weir and Swiss Tower Mills align on energy efficient comminution pathway

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The Weir Group has announced a new alliance with Swiss Tower Mills Minerals (STM) in which Weir will market STM’s vertical stirred grinding mills for coarse grinding applications worldwide.

Integrating vertical stirred grinding mills into Weir’s minerals processing flowsheet will provide customers substantial improvements in throughput and energy efficiency, helping them to meet their productivity and sustainability goals, Weir says.

STM’s vertical stirred grinding technology is proven for energy efficient comminution in the mining market with more than 80 units currently operating in the hard-rock mineral processing industry across the globe, according to the company. It is used within the comminution segment of the minerals processing circuit as part of a series of crushing and grinding processes that create the fine particles from which minerals can be extracted through flotation.

Comminution, as has been well documented, is one of the most energy intensive parts of the mine, accounting for 25% of the final energy consumption of an average mine site.

Weir says it is already a leader in comminution technologies, offering solutions such as Enduron® high pressure grinding rolls (HPGRs) to drive down energy consumption by around 40% for customers.

This new alliance with STM takes things to the next level, offering the mining and minerals industry a proven low energy alternative to traditional high energy consuming tumbling mills, it said. Combining and integrating these energy-efficient technologies into a single, optimised flowsheet will deliver significant reductions in energy use, driving down costs and carbon emissions.

In order to prove the most beneficial flowsheet for specific projects, STM has already supplied two vertical test mills to the Weir Minerals HPGR test facility in Venlo (Netherlands). This will put Weir and STM in the unique position to provide clients combined energy efficient grinding test work of HPGR followed by STM’s vertical stirred mill, they said.

Ricardo Garib, Weir Minerals Divisional President, said: “Weir and STM share the same vision of enabling primary resource providers to produce resources in the most sustainable manner. This is a perfect match of best-in-class technology providers. Integrating STM mills with Weir’s comminution products, which includes Enduron HPGRs and Enduron screens, will improve throughput and help bring substantial reductions in carbon emissions.

“This is a real win-win.”

Fritz Moser, STM Chairman, said “Both the HPGR and the STM vertical stirred mills provide significant energy savings compared to conventional grinding technologies. Our new supply agreement with Weir will enable us to fast track the roll out of an innovative flowsheet using STM mills in conjunction with Weir’s Enduron HPGR.”

Kışladağ and Weir Minerals on the HPGR-backed gold recovery trail

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The story that led to the installation of a Weir Minerals Enduron® high pressure grinding roll (HPGR) at Eldorado Gold’s Kışladağ heap leach operation in Turkey is a fascinating read, as well as a great example of the benefits of using such technology.

Back in March 2018, Eldorado announced it would suspend mining to evaluate processing options for the operation. This decision followed extensive laboratory tests that indicated gold recoveries would continue to trend downwards around the base of the open pit where mining was underway.

This suspension, plus further engineering and test work, led to the company advancing the potential development of a mill project. The transition away from its heap leaching roots to a possible mill and carbon-in-leach (CIL) process would have added significant capital costs and shortened the mine life significantly.

Before making this significant capital decision, Eldorado paused to take time to undertake the necessary technical work and sought the technical collaboration of Weir Minerals on a solution.

“It was a very challenging period,” George Burns, President & CEO of Eldorado Gold Corporation, told IM. “Kışladağ is a cornerstone asset in our portfolio. It required collaboration with our geologists, metallurgists, site teams and technology providers, including Weir, working together on a solution.”

(Credit: Eldorado Gold)

In late 2018, results showed increased recoveries from an extended leach cycle. Following a deeper understanding of the geometallurgical drivers of the sulphide component of the deposit, improved heap leach recoveries were realised by optimising the metallurgical conditions. With these improved recoveries confirmed, the heap leach plan was revised in early 2019. Eldorado announced plans to resume mining, crushing, stacking and heap leaching at Kışladağ, and suspended plans to build the processing plant.

The decision came following metallurgical test work on the material placed on the heap leach pad in 2018. Gold recovery had increasingly exceeded expectations throughout the year, providing a new, positive heap leaching outlook beyond the near term. At the same time, Eldorado worked with Weir Minerals on the potential use of an HPGR at the operation.

HPGR creates a finer particle size, which helps to liberate the gold particles, resulting in increased recoveries.

An improved understanding of the leaching process on its low-grade ore and the potential of this cost-effective grinding addition provided it with the confidence to continue heap leaching beyond the short-term time horizon previously envisaged.

“Our collaboration with Weir on this effort is an excellent example of how Eldorado collaborates with technology leaders and seeks out solutions,” Burns said. “We believe this is a strength of the company’s core business values. We are agile and flexible ‒ a good example in both business and operations to find innovative, technical solutions and demonstrate prudent capital discipline. Ultimately, the solution was the best technical and economic decision for Eldorado.”

Testing, testing, testing

“The relationship between Weir Minerals’ and Kışladağ goes back to 2013,” Bjorn Dierx, Global Product Manager Enduron HPGR, told IM.

The OEM had been provided with samples on several occasions to investigate different flowsheet possibilities.

“The benefits of HPGR in heap leaching recovery were known by the site’s crew,” he said.

Enduron technology was tested at the quaternary crushing stage before heap leaching, in the quaternary crushing stage before ball milling and at the tertiary crushing directly before heap leaching.

All the time, the mine operator, Tuprag, Eldorado Gold’s subsidiary in Turkey, was evaluating the impact on gold recovery.

Although HPGR in closed circuit with screening was also tested, most of the test campaigns were focused on a configuration with so-called ‘Partial Product Recycling’ (PPR), according to Serhat Onol, Weir Minerals Senior Process Engineer.

“This system includes splitter plates underneath the rolls which ‘cut’ a proportion of the product discharge and reverts this back to the HPGR head feed,” he explained. “This recycle stream can be adjusted online to adapt the product grind towards the downstream requirements.”

PPR is not an option for every application but for Tuprag – due to the feed and desired product size – all specifications showed it was the best route.

“The hybrid solution with screening serves to increase the flexibility and to control the circulating load to the HPGR,” Onol said.

With capacity rates of around 4,200 t/h at Kışladağ, the screening area requirement was reasonably high, he explained.

“The hybrid solution uses screening only for the recirculating stream: the centre product of the HPGR reports to downstream leaching, whereas the rest is recirculated,” he said. This not only removes the fines re-entering the HPGR and, thus, reduces the circulating load, but also avoids the over-grinding of fines before leaching.

The PPR option, itself, is a very flexible operation, with the adjustable discharge splitter plates providing the best circuit flexibility in terms of throughput and product size, according to Onol.

(Credit: Eldorado Gold)

Great expectations

With the main driver of the HPGR installation being an improved gold recovery scenario, leading to an increased heap leach life, the pressure has been on Weir Minerals to come up with the goods.

The final flowsheet, which includes a 2.4 m diameter by 2.2 m long Enduron HPGR with the capacity to process 4,200 t/h, is much simpler than the existing circuit, according to Dierx, with less equipment to maintain, control and monitor.

“A single Enduron HPGR will replace all of the five existing tertiary crushers of which liners would have an average lifetime of circa-one month with a crusher availability of 85%,” he said. “The HPGR tyres have a wear life close to 18 months, with the HPGR achieving a high asset availability of more than 95%.

“Additionally, as a result of the HPGR combined with the hybrid PPR system, the existing four tertiary screens are also being decommissioned.”

Not only has the HPGR alleviated the use of this equipment, it is also set to boost that bottom line gold recovery.

“During testing, it was determined that the circuit configuration and HPGR operating conditions, such as pressure, have a direct influence on the gold recovery,” Dierx said. “The current expectation is that the average recovery increase after the commissioning of the Enduron solution will be approximately 4%.”

This could bring gold recovery to approximately 56%, as was declared in a 2020 press release from Eldorado that highlighted a 15-year mine life at Kışladağ with an average annual production of 160,000 oz.

In action

One of the largest brownfield HPGRs Weir Minerals has ever installed has just processed its first material at Kışladağ, which is testament to the hurdles both the Weir Minerals and Tuprag teams overcame during the height of the COVID-19 pandemic.

“Despite the challenges we faced during the pandemic, we were able to fully install the machine, including pre-commissioning, in only 22 weeks,” Dierx said.

(Credit: Eldorado Gold)

This was achieved by minimising the amount of work carried out on site via pre-site testing and modular HPGR assembly.

“As the available footprint in existing sites is limited, the unique Enduron design (length:diameter ratio) not only improves the grinding efficiency but also allows for easier implementation with less civil requirements,” Dierx said.

The machine has the potential to be digitally connected to the Weir Synertrex® IoT platform where operators can benefit from direct access to maintenance specialists, who will be monitoring performance and provide necessary operating guidance.

And the Weir Minerals team is confident more Enduron HPGR installations will follow the one at Kışladağ.

“We are very proud of the product’s recognition by our customers as the Enduron HPGR has been selected for all major greenfield HPGR projects in the hard-rock space,” Dierx said. “Despite all the key Enduron differentiators, it is not only merely about the product but particularly the wider experience across Weir Minerals in both the upstream and downstream processes via our wide product portfolio.

“Particularly in these brownfield applications, the system is not operating in a vacuum and every process change influences how the overall circuit works. This requires tacit knowledge, which Weir Minerals holds across their global teams.”

Eldorado’s Burns concluded: “We are pleased to implement a solution that increases gold recovery and supports a 15-year mine life at Kışladağ, allowing Eldorado to continue to provide employment and economic opportunity in the region, as well as provide a solid foundation for future growth.

“Kışladağ has been the cornerstone asset of Eldorado for over a decade, producing over 3 Moz of gold and generating significant value for all stakeholders during that period. This project is a testament to our exceptional team and technology partners working together to execute in challenging circumstances during the pandemic.”

Weir Minerals wins large comminution order from Nigeria iron ore mine

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Two of the largest screens built by Weir Minerals Africa are being designed and manufactured in South Africa as part of a process solution for an iron ore mine in Nigeria.

According to Tiisetso Masekwameng, General Manager Comminution at Weir Minerals Africa, the flowsheet accepted by the customer includes equipment for screening, washing, and grinding supplied by Weir Minerals.

“Within our scope of work are the two largest Enduron® double-deck banana screens built by Weir Minerals,” Masekwameng says. “This is made possible by the depth of design expertise in our Separation Technology Group, an eight-strong team conducting research and development.”

Steven Hunter, Separation Technology Group Leader at Weir Minerals Africa, says the two 51 t Enduron double-deck banana (DBHG 43/97) screens (one pictured) for this project were built upon the designs of the existing Weir Minerals screens range. These large machines measure 4.3 m wide and 9.7 m long and can process 1,750 t/h.

“The customer’s production requirements demanded this considerable size, so we optimised the design by minimising mass without compromising structural integrity,” Hunter says. “We conducted extensive finite element analysis on the whole machine but focused on the main structural elements, ensuring that the units were fit-for-purpose while still being light enough to be driven by the exciters.”

The size of the units still demanded the design and manufacture of Weir Minerals Africa’s largest exciter yet – the Enduron LTX 10. With 120 t of excitation force (at maximum setting), these units will drive the screens at a stroke of 9.4 mm and a gravitational force of 4.6 G.

Hunter said the screens are ready to be fitted with Weir’s IIoT platform, Synertrex. “This allows the machines to be monitored remotely; the system can measure the machine’s performance and any deviations arising that may require proactive attention,” he explained.

The order for Nigeria also includes two Trio® jaw crushers, two Trio cone crushers, two large 2 m by 8 m Trio apron feeders, two Trio pan feeders, eight Enduron vibrating screens and an Enduron HPGR.

For the clay washing circuit, Weir Minerals Africa will supply the mine with a Trio twin-shaft blade mill and Trio twin-shaft coarse washers as well as Warman® slurry pumps.

Weir adds aftermarket and service contract to Iron Bridge remit

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The Weir Group says it has won a £95 million ($127 million) order to provide aftermarket components and service to the Iron Bridge magnetite project in Western Australia.

The aftermarket contract follows Weir’s success in winning a record £100 million order for original equipment for the Iron Bridge project in 2019, including its Enduron® High Pressure Grinding Rolls (HPGRs, pictured) that, it says, will enable dry processing of ore and use at least 30% less energy than traditional alternatives.

The Iron Bridge magnetite project is a $2.6 billion joint venture between Fortescue Metals Group’s subsidiary FMG Magnetite Pty Ltd and Formosa Steel IB Pty Ltd located in the Pilbara region, around 145 km south of Port Hedland.

Both the aftermarket order and revenues will be recognised over the seven-year period of the agreement, which starts in 2022, in line with the 22 Mt/y project’s initial production.

Ricardo Garib, President of Weir Minerals, said: “This is another landmark order for Weir. Having helped design an energy and water efficient magnetite processing plant, we are delighted to provide operational support for Iron Bridge from 2022. It is an excellent example of the value that Weir’s innovative engineering and close customer support can create for all our stakeholders and reflects the key role we have to play in making mining operations more sustainable and efficient.”

Weir’s Enduron HPGRs are increasingly replacing conventional mills in comminution circuits, Weir says. In addition to their energy and water savings, they also reduce grinding media consumption, while their wearable components last longer, reducing maintenance costs. Additionally, HPGRs contribute significantly to carbon dioxide emission savings.

Stuart Hayton, Managing Director of Weir Minerals Netherlands, where the Enduron HPGRs are designed and manufactured, said: “This is an important project for Weir and for the broader mining industry. We know comminution is one of the most energy intensive parts of the mineral process and, with our Enduron HPGRs, we have a unique ability to offer significant cost, energy and water savings to customers around the world. As the mining industry evolves, we are commited to continuing to innovate, reducing miners’ costs and environmental impact.”

This latest contract award means Weir now has more than £200 million of orders from the Iron Bridge project including its Enduron HPGRs, GEHO® and Warman® pumps, Cavex® hydrocyclones and Isogate® valves.

To support the project and future growth, Weir says it will build a new service centre in Port Hedland, Western Australia, thereby providing employment and training opportunities in the area, with a particular emphasis on supporting greater Aboriginal representation in the broader mining workforce.

New Weir Minerals Sand Wash Plant to boost recoveries

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Weir Minerals has released a complete sand wash solution that draws on its long experience in the sand and aggregate industry.

The Weir Minerals Sand Wash Plant comes with Linatex® lining, produces more saleable product than conventional sand screw plants, with fewer moving parts, and has an optimised process that produces a drier, higher-quality product with less fines, according to the company.

The solution has already proven effective at sites like Coimbatore Minerals in Tamil Nadu, India, Weir says, where a custom-built wash plant reduced its total cost of ownership by 51%, while offering a 23% reduction in fines that helped the company consistently meet the industry’s high standards for a saleable product.

Bruce Cooke, Global Product Manager – Sand Wash Plants for Weir, said: “We know the most important thing for quarry operators in washing is recovering as much sand as possible to maximise their sales, which is why we’ve designed an integrated solution for washing their product, with a hydrocyclone which can deliver greater recovery than sand screws. In addition, every component has been selected by our expert engineers for its long-service life, interoperability and ease of maintenance.”

The compact solution features a range of Weir Minerals equipment designed for high efficiency in sand and aggregate applications, including Warman® WGR pumps, Cavex® hydrocyclones, Enduron® dewatering screens, Linatex hoses and Isogate® knife gate valves.

The Warman WGR is a popular pump in the sand extraction industry, according to Weir, combining top of the line hydraulic design with an adjustable impeller, long bearing life and a simplified wet end, making replacement predictable and cost effective.

Precision moulded and lined, Linatex premium rubber is used for wear zones throughout the plant due to its proven wear performance in wet sand applications in operations around the world, Weir said.

Cavex hydrocyclones provide “exceptional classification efficiency” thanks to their unique 360° laminar spiral, delivering more saleable product than a sand screw solution would, the company said. Enduron dewatering screens, meanwhile, reliably separate product with a high degree of efficiency. And, finally, Isogate knife gate valves contribute to the plant’s straightforward maintenance.

Surendra Menon, President, Weir Minerals India, said: “For the new sand wash plant, we focused on making it quick and easy for quarry operators to get up and running. Its straightforward design means it can be assembled in just two days while its compact skids make it easy to drag into any operation.

“Efficient, reliable and easily integrated into flowsheets, we think the plant is a game changer for quarry owners.”

Weir Minerals Africa putting newly designed vibrating screens to the test

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Weir Minerals Africa, having over the last 40 years proven the credentials of its Enduron® range of vibrating screens, is now locally designing and manufacturing new-generation linear motion vibrating screens.

One of these new, modern screen designs is part of a recent Weir Minerals Africa complete comminution plant contract for a South Africa mining project. The scope included two crushing stations, a screening station and all the related feed chutes, bins and conveyors.

According to Christian Stehle, Head of Engineering at Weir Minerals Africa, the company’s design capability provides the flexibility to produce vibrating screens to suit each customer’s plant layout. At the same time, the designs will optimise cost, efficiency and performance. South Africa also hosts Weir Minerals’ global screening and separation technology group.

“This expertise ensures that our robust Enduron vibrating screens provide exceptional classification and dewatering screening performance,” Stehle said. The screens are deployed in a wide range of minerals processing applications.

He noted that vibrating equipment is generally more challenging to design than static equipment due to the high frequency cyclic loading to which the machines are subjected.

“The final design must address key criteria like screening efficiency, throughput and loading, while still operating within the acceptable fatigue life limits of the materials of construction,” he said.

Stehle highlighted that the use of finite element analysis (FEA) tools allow engineers to optimise screen life by obtaining the stress and deflection levels in the equipment and applying the appropriate structural design and utilisation of materials in the areas experiencing high stresses.

“Traditionally, screen designs used to be heavier in an effort to extend the life of the equipment,” he said. “Using FEA tools during the design stage allows us to retain structural integrity while actually reducing the overall weight of the machine.”

While there are areas of high stress on the equipment that need more strength, technology tools indicate where lower stresses occur. In these areas, less steel can be used to make the structure lighter, according to Weir Minerals Africa. Leveraging this technology, the weight of some new-generation screens has been cut by up to 15%, the company said.

Stehle noted that Weir’s Synertrex™ IoT platform can also be applied to monitor and improve the performance of the company’s vibrating screens. Synertrex technology is an industrial internet of things system that allows operators to monitor every aspect of their equipment’s operation, to prevent problems and increase throughput.

Weir Minerals gives its skew view on HPGRs

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With industry demand for high pressure grinding rolls (HPGR) on the up, Weir Minerals is arguing that skewing is a vital feature for modern HPGRs to reduce wear, save downstream energy and ensure optimal grinding across the whole feed.

The company was sharing its findings following the publication of a new white paper.

Weir said: “With their excellent throughput capacity, low maintenance requirements and energy efficiency, HPGRs are fast becoming a go-to for greenfield projects looking to maintain their margins despite commodity price pressures and declining ore grades.”

The mineral processing company said, in the June quarter, that it had registered strong demand for its Enduron® HPGR technology during the three-month period, later on in the year confirming a major order, which included this comminution equipment, from Fortescue Metals Group for its Iron Bridge magnetite project in Western Australia.

Henning Knapp, HPGR Process Team Leader for Weir Minerals, said the applications from this equipment have evolved from the cement production days of the 1980s and are increasingly being deployed as tertiary and quaternary crushers in mineral comminution circuits, dealing with tougher ores including iron, gold, copper and diamonds.

“As any engineer will tell you, it’s almost impossible to eliminate feed variance and segregation completely. In the past, this has posed a critical challenge for HPGR operators – but dynamic skewing such as that featured in the Enduron HPGR, maintains optimal pressure across the entire feed.”

Traditionally, HPGR manufacturers have shied away from skewing designs, for fear of roller misalignment creating unfavourable load distributions, and preventing the use of flanged guards to reduce the edge effect, the company said. “However, Weir Minerals’ unique roller bearings design allows for skewing alongside effective edge guards, reducing wear and promoting better grinding.”

The downside of static rollers

A HPGR reduces particles by compressing and crushing the feed between two equally sized, parallel rollers rotating in opposite directions, with a small gap between them. This compresses the feed to 80% of its solid density, where the force of the rollers pushes the rocks against each other and exceeds their compressive strength.

“Inter-particle comminution avoids the direct component wear caused by conventional comminution techniques, and applies immense pressure, up to 27,000 kN, across the entire particle size distribution, which creates the higher proportion of fines HPGRs are renowned for,” says Knapp.

However, segregated feeds can result in markedly uneven particle sizes across the width of the feed, creating high, abrasive pressure on one side of the roll and insufficient pressure on the other. It will also produce a coarser product, requiring more work downstream, according to Weir.

“To compensate for the edge effect, a lateral wall or ‘cheek plate’ is deployed on either side to prevent material exiting the gap between the rollers sideways. The closer this is to the rollers, the better – but that has prevented engineers from introducing the flexibility needed to cope with feed segregation,” explains Knapp.

How Enduron HPGRs skew to maintain optimum pressure

To accommodate this uneven pressure Enduron HPGRs use a spring-loaded lateral wall which not only reduces the edge effect (maintaining a gap of as little as 1 mm) but is specifically designed to facilitate roll skew.

As shown above, an uneven feed will lead to high pressure on one side and not enough on the other. Having one roller skew will facilitate larger material at one end while ensuring the smaller particles on the other side receive enough pressure to be ground down: it maintains an even pressure distribution across the entire feed, saving energy and reducing wear, Weir says.

“The degree to which the Enduron HPGRs skew is largely dependent on the width of the roll, with longer rolls skewing about 5 mm for every metre the roll is wide. However, the effect of even small changes can be significant on local pressure peaks,” says Knapp.

“The skewing should be managed by an advanced control system, which steers the rolls to satisfy the desired output pressure. This system also ensures the skew isn’t too great or maintained for too long, which both disrupt the compressive bed.”

In the case of prolonged or excessive skewing, Enduron HPGRs send a signal notifying the supervising control system and operating staff. Prolonged skewing generally is indicative of a disturbance or fault in up-stream facilities, such as low bunker filling, upstream crusher wear, screen deck wear, or conveyor failure, Weir says.

“Where static rolls suffer from differential pressure, creating undesired product, consuming more energy and suffering additional wear, Enduron HPGRs maintain optimum pressure across the entire feed thanks to their skewing, spring-loaded lateral walls,” Weir said.

Knapp concluded: “When dealing with competent mineral feeds in real-world conditions, there’s simply no substitute for the Enduron HPGR’s ability to maximise performance with skewing.”

Weir secures largest-ever individual mining order from Fortescue

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The Weir Group says it has been awarded a £100 million ($123 million) order to provide industry-leading energy saving solutions to the Iron Bridge magnetite project, a joint venture between Fortescue Metals Group and Formosa Steel IB.

The order, which includes a range of Weir crushing and pump equipment including Enduron® high pressure grinding rolls (HPGRs) and GEHO® pumps, will reduce energy consumption and wet tailings waste by more than 30% compared with traditional mining technologies, according to the equipment manufacturer.

The Iron Bridge project, 145 km south of Port Hedland in the Pilbara region of Western Australia, is a $2.6 billion investment in premium magnetite iron ore reserves with annual production, when the mine is fully operational, of 22 Mt/y of 67% Fe concentrate. Delivery of the first ore is expected in 2022.

When the mine build was approved back in April, Fortescue CEO, Elizabeth Gaines, said the innovative design for the project, which included the use of a dry crushing and grinding circuit, “will deliver an industry-leading energy efficient operation with globally competitive capital intensity and operating costs”.

A pilot project to verify the Iron Bridge project design involved processing 1 Mt of ore through a full scale HPGR and air classifier, according to Fortescue.

Weir Group Chief Executive Officer, Jon Stanton, said: “We are delighted to have secured this landmark contract, which is Weir’s largest-ever individual mining order.

“Fortescue challenged us to help create one of the most energy and cost-efficient magnetite ore processing facilities in the world. Our engineers have worked relentlessly to design a solution that is truly innovative – delivering significant energy, water and cost savings. This is a great example of working in close partnership with an ambitious customer who shares our passion for using innovative engineering to make mining more productive and sustainable.”

Ricardo Garib, President of the Weir Minerals division, added: “Our team are really enjoying working with Fortescue. Our engineers relish a challenge and it has been great to work on a project that demonstrates the substantial cost and environmental savings that our range of solutions can offer.

“As more mines look to increase productivity, we look forward to even more opportunities to leverage our combination of passionate people, innovative solutions and comprehensive global service capability.”

Weir’s Enduron HPGRs are increasingly replacing conventional mills in comminution (crushing, screening and grinding) circuits because of their substantially lower energy consumption and potential for significant total cost of ownership reduction, Weir says.

“Not only do they require as much as 40% less energy than traditional alternatives, but their wearable components last much longer and the maintenance time required to replace worn out parts is significantly lower.”

The company outlined the reasons why companies are turning to Enduron HPGRs in a blog post earlier this week.